The Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center (LA Biomed) General Clinical Research Center (GCRC) is applying for a Liquid Chromatography Tandem Mass Spectrometer (LC-MS/MS) for the GCRC Core Laboratory and the Biomedical Mass Spectrometry Facility. The LC/MS/MS is requested to serve the needs of clinical and translational investigators at Harbor-LA Biomed and our sister institutions in Los Angeles (Cedars Sinai Medical Center (Cedars-Sinai), UCLA-Westwood, and the Charles Drew University of Health and Science (Drew)). The sharing of the services of this equipment is an important part of our preparation for a joint application for a Clinical and Translational Sciences Institute (CTSI) across the four sister institutions. To avoid duplication, increase efficiency and optimize utilization in the laboratory, the program and laboratories directors of the GCRCs at UCLA Westwood, Cedars-Sinai, Harbor-LA Biomed and Drew have agreed to designate the Harbor-UCLA GCRC Core Lab and Biomedical Mass Spectrometry facility as the central Endocrine and Metabolism Core Laboratory for all four CTSI institutions. Currently, the GCRC Core Laboratory provides hormone and vitamin analyses mostly by immunoassays. These methodologies have higher variance, poorer reproducibility and in many instances less accuracy than that obtained from LC/MS/MS. The challenges of clinical assays of small molecules in research include the requirements of high sensitivity and low limit of quantitation (LOQ) into the low fentomolar range. Such sensitivity is necessary in order to be able to accurately diagnose hormonal or vitamin deficiency and to monitor its treatment in men, women and children. Our current investigators include 6 major NIH users with 15 protocols, 9 NIH funded users and 6 other junior and funded investigators. These investigators are engaged in a wide spectrum of research spanning from metabolic bone diseases inflicting children and the elderly, hormonal deficiencies in men and women, hormone and non-hormone dependent cancers, co-morbidities of HIV disease and importantly, understanding mechanisms underlying these diseases. With expansion of validated assay portfolio we anticipate that we can support more than twice the research protocols. This application is strongly supported by all four participating institutions. The strengthening of the Core Facilities providing Mass Spectrometry Technology capability will also significantly enhance our ability to serve not only our institution but our sister institutions at UCLA, Cedars-Sinai, and Drew in Southern California and our diverse and often underserved patient population. PUBLIC HEALTH RELEVANCE: The Harbor-UCLA General Clinical Research Center is requesting the funding of a state of the art, high-throughput liquid chromatography tandem mass spectrometer to measure serum hormones and other metabolic products in human bodily fluids. This will allow the measurement of very small amounts of these hormones and chemicals with very high selectivity, accuracy and precision. The application of this method will support many investigators from LA BioMed, Cedars-Sinai, UCLA-Westwood and Drew University in the diagnosis and monitoring of treatment of many metabolic, endocrine, kidney an bone disease for our underserved population.